There is little clinical data available on the use of alternative surgical techniques beyond castration for producing sterility in the male dog and cat. Furthermore, only limited data exist on the effect of vas deferens severance or blockage on the dog, and no information has been published of the effects of similar surgical procedures in the cat. In this study, a laparoscopic technique was developed to occlude the vas deferens in dogs and cats. The effects of this surgical procedure on pubertal onset, libido, sperm production, testicular volume, and general animal health has been investigated. Results indicated that there were no adverse effects resulting from laparoscopic vas occlusion with regard to onset of sexual activity or copulatory ability. Sperm counts in adult dogs and cats decreased to zero within two and five days, respectively. Histological examination demonstrated that spermatogenesis was normally active in all animals. Granuloma formation was confirmed in vas deferens biopsies in one-half the animals in each group, but this finding had no apparent compromising effect on general animal health.